# New to Julia

**URL:** https://discourse.julialang.org/c/first-steps/8.md?page=12

[Latest](https://discourse.julialang.org/latest.md) · [Categories](https://discourse.julialang.org/categories.md) · [Tags](https://discourse.julialang.org/tags.md)

**Page:** 13

---

## [Plotting function returning complex vector](https://discourse.julialang.org/t/plotting-function-returning-complex-vector/130393)

<div class="topic-metadata">

**Author:** [@rokke](https://discourse.julialang.org/u/rokke)\
**Replies:** 7\
**Last updated:** [July 2, 2025, 8:34am UTC](https://discourse.julialang.org/t/plotting-function-returning-complex-vector/130393 "2025-07-02T08:34:02Z")

</div>

I have some functions which each return a constant n number of complex values, and would like to plot one as a series of lines on the complex plane. if I do something like plot(real.(\[f.(0.1:.1:5)...;;\]'),-imag.(\[f.(0.1…

---

## [Use of complex numbers in ModelingToolkit using @mtkmodel macro](https://discourse.julialang.org/t/use-of-complex-numbers-in-modelingtoolkit-using-mtkmodel-macro/130332)

<div class="topic-metadata">

**Author:** [@JaviJR](https://discourse.julialang.org/u/JaviJR)\
**Replies:** 1\
**Last updated:** [June 30, 2025, 10:32am UTC](https://discourse.julialang.org/t/use-of-complex-numbers-in-modelingtoolkit-using-mtkmodel-macro/130332 "2025-06-30T10:32:18Z")

</div>

Hello, I’ve been running some tests with ModelingToolkit, and when trying to implement equations that use complex numbers using @mtkmodel macro, I haven’t been able to assign initial values to the system without it fail…

---

## [How to implement amplitude damping and phase damping noise in Yao.jl?](https://discourse.julialang.org/t/how-to-implement-amplitude-damping-and-phase-damping-noise-in-yao-jl/130123)

<div class="topic-metadata">

**Author:** [@google\_xu](https://discourse.julialang.org/u/google_xu)\
**Replies:** 1\
**Last updated:** [June 30, 2025, 8:27am UTC](https://discourse.julialang.org/t/how-to-implement-amplitude-damping-and-phase-damping-noise-in-yao-jl/130123 "2025-06-30T08:27:49Z")

</div>

I’m new to Yao.jl and want to simulate quantum noise models, specifically amplitude damping and phase damping. However, I couldn’t find built-in support for these noise types in the official documentation. Could someone …

---

## [Extracting chains individual initial step size from Turing chain object saved (serialize) after run](https://discourse.julialang.org/t/extracting-chains-individual-initial-step-size-from-turing-chain-object-saved-serialize-after-run/130272)

<div class="topic-metadata">

**Author:** [@Sahil\_Khan](https://discourse.julialang.org/u/Sahil_Khan)\
**Replies:** 1\
**Last updated:** [June 29, 2025, 8:21am UTC](https://discourse.julialang.org/t/extracting-chains-individual-initial-step-size-from-turing-chain-object-saved-serialize-after-run/130272 "2025-06-29T08:21:55Z")

</div>

Hello, I was wondering is there any way to extract individual step size for chains I run in parallel ? I tried summarize() but it just gives mean and sd value. Thank you

---

## [Reference tests fail locally but pass on GitHub Actions](https://discourse.julialang.org/t/reference-tests-fail-locally-but-pass-on-github-actions/130271)

<div class="topic-metadata">

**Author:** [@simonsteiger](https://discourse.julialang.org/u/simonsteiger)\
**Replies:** 8\
**Last updated:** [June 29, 2025, 7:56am UTC](https://discourse.julialang.org/t/reference-tests-fail-locally-but-pass-on-github-actions/130271 "2025-06-29T07:56:13Z")

</div>

Hi, I have recently run into a strange problem with reference tests while working on a visualisation package. The tests worked fine but have started failing since I changed the compat for Makie.jl and MCMCChains.jl (thi…

---

## [Creating columns in DataFrame via loops](https://discourse.julialang.org/t/creating-columns-in-dataframe-via-loops/130287)

<div class="topic-metadata">

**Author:** [@Snowy](https://discourse.julialang.org/u/Snowy)\
**Replies:** 3\
**Last updated:** [June 27, 2025, 10:51pm UTC](https://discourse.julialang.org/t/creating-columns-in-dataframe-via-loops/130287 "2025-06-27T22:51:40Z")

</div>

Hi all, Stuck on what is probably a super simple problem. It’s the end of the week at 4pm on a Friday so my brain is just no longer working :blush: I want to create a columns on an existing data frame with a specified …

---

## [Using Docker image on Julia](https://discourse.julialang.org/t/using-docker-image-on-julia/130242)

<div class="topic-metadata">

**Author:** [@Methmika\_Jayawardene](https://discourse.julialang.org/u/Methmika_Jayawardene)\
**Replies:** 1\
**Last updated:** [June 26, 2025, 11:37pm UTC](https://discourse.julialang.org/t/using-docker-image-on-julia/130242 "2025-06-26T23:37:06Z")

</div>

Hello guys, I have a Docker image that you can find on this link, GitHub - Universite-Gustave-Eiffel/waveguicsx: waveguicsx, a python library for solving complex waveguide problems. I would like to know if it is possi…

---

## [Adding an SMatrix](https://discourse.julialang.org/t/adding-an-smatrix/130202)

<div class="topic-metadata">

**Author:** [@matthiasbaitsch](https://discourse.julialang.org/u/matthiasbaitsch)\
**Replies:** 3\
**Last updated:** [June 25, 2025, 4:23pm UTC](https://discourse.julialang.org/t/adding-an-smatrix/130202 "2025-06-25T16:23:10Z")

</div>

Hi, the following code fails because Ke is immutable after adding the SMatrix. using StaticArrays Ke = zeros(3, 3) Ke += SA\[1 2 3; 4 3 2; 4 3 2\] Ke\[1, 1\] += 3 I wonder whether this is intended behaviour.

---

## [What's the feasibility of and interest in tooling for building desktop science, engineering and analysis tools?](https://discourse.julialang.org/t/whats-the-feasibility-of-and-interest-in-tooling-for-building-desktop-science-engineering-and-analysis-tools/130094)

<div class="topic-metadata">

**Author:** [@MDSW](https://discourse.julialang.org/u/MDSW)\
**Replies:** 3\
**Last updated:** [June 24, 2025, 6:41pm UTC](https://discourse.julialang.org/t/whats-the-feasibility-of-and-interest-in-tooling-for-building-desktop-science-engineering-and-analysis-tools/130094 "2025-06-24T18:41:41Z")

</div>

I’ve been doing some small proof-of-concepts while getting deeper on some of the technical aspects of Julia around compilation and deployment packaging. I’m drawn to Julia as a result of having seen the challenges with t…

---

## [Recommended practices for trying out packages without polluting global env](https://discourse.julialang.org/t/recommended-practices-for-trying-out-packages-without-polluting-global-env/129912)

<div class="topic-metadata">

**Author:** [@lunafazio](https://discourse.julialang.org/u/lunafazio)\
**Replies:** 6\
**Last updated:** [June 22, 2025, 10:22am UTC](https://discourse.julialang.org/t/recommended-practices-for-trying-out-packages-without-polluting-global-env/129912 "2025-06-22T10:22:42Z")

</div>

I am aware of activate --temp, but adding any package always seems to involve a lot of precompilation, so not ideal for quickly testing things. Are there some additional convenience options for --temp that I am overlook…

---

## [Stucked at Found FFTW wisdom at C:\\Users\\Administrator\\.julia\\scratchspaces\\30eb0fb0-5147-11e9-3356-d75b018717ce\\lunacache\\FFTWcache\_1threads](https://discourse.julialang.org/t/stucked-at-found-fftw-wisdom-at-c-users-administrator-julia-scratchspaces-30eb0fb0-5147-11e9-3356-d75b018717ce-lunacache-fftwcache-1threads/130086)

<div class="topic-metadata">

**Author:** [@jiahui](https://discourse.julialang.org/u/jiahui)\
**Replies:** 2\
**Last updated:** [June 21, 2025, 8:06pm UTC](https://discourse.julialang.org/t/stucked-at-found-fftw-wisdom-at-c-users-administrator-julia-scratchspaces-30eb0fb0-5147-11e9-3356-d75b018717ce-lunacache-fftwcache-1threads/130086 "2025-06-21T20:06:00Z")

</div>

Hello, I’m using Luna package to simulate the pulse propogation in a fiber with simple code: using Luna output = prop\_capillary(125e-6, 3, :He, 1; λ0=800e-9, energy=120e-6, τfwhm=10e-15, λlims=(150e-9, 4e-6), trange=1…

---

## [Refinement meshgrids](https://discourse.julialang.org/t/refinement-meshgrids/129982)

<div class="topic-metadata">

**Author:** [@Cyan](https://discourse.julialang.org/u/Cyan)\
**Replies:** 3\
**Last updated:** [June 21, 2025, 12:07pm UTC](https://discourse.julialang.org/t/refinement-meshgrids/129982 "2025-06-21T12:07:24Z")

</div>

Hi, all. I am trying to plot the curves of potential 1/r on mesh grid xg and yg (xg and yg are 2d mesh grids, r = @. sqrt(xg^2 + yg^2)). I want to solve the curves where the potential equals 1. I want to refine the grid…

---

## [Periodic linear advection](https://discourse.julialang.org/t/periodic-linear-advection/130003)

<div class="topic-metadata">

**Author:** [@Tanya123](https://discourse.julialang.org/u/Tanya123)\
**Replies:** 0\
**Last updated:** [June 18, 2025, 8:05pm UTC](https://discourse.julialang.org/t/periodic-linear-advection/130003 "2025-06-18T20:05:54Z")

</div>

I’m trying to numerically advect a scalar field β(x, y, t) only in the x-direction (no y-advection), mimicking a shifting pattern like β(x - ct). I’m using ModelingToolkit.jl to solve the PDE, but my code hangs after th…

---

## [Problems with Julia QML and VSCode](https://discourse.julialang.org/t/problems-with-julia-qml-and-vscode/129999)

<div class="topic-metadata">

**Author:** [@FSUfan](https://discourse.julialang.org/u/FSUfan)\
**Replies:** 4\
**Last updated:** [June 18, 2025, 7:02pm UTC](https://discourse.julialang.org/t/problems-with-julia-qml-and-vscode/129999 "2025-06-18T19:02:45Z")

</div>

First, I apologize for the 74 error lines, but since there are multiple objects involved and I don’t know where to upload the text file… sorry but there are many elements involved I am trying to run some examples in Git…

---

## [Mesh grids and position array tranform](https://discourse.julialang.org/t/mesh-grids-and-position-array-tranform/129983)

<div class="topic-metadata">

**Author:** [@Cyan](https://discourse.julialang.org/u/Cyan)\
**Replies:** 3\
**Last updated:** [June 18, 2025, 12:34pm UTC](https://discourse.julialang.org/t/mesh-grids-and-position-array-tranform/129983 "2025-06-18T12:34:43Z")

</div>

I am working on the mesh grids, I want to ask whether there is quick transformation and inverse transformation between array\_x and flat\_x? array\_x = \[ \[1, 1, 1, 1\], \[2, 2, 2, 2\], \[3, 3, 3, 3\]\] a…

---

## [Subtyping directly in parametrics Types](https://discourse.julialang.org/t/subtyping-directly-in-parametrics-types/129949)

<div class="topic-metadata">

**Author:** [@eotero](https://discourse.julialang.org/u/eotero)\
**Replies:** 10\
**Last updated:** [June 17, 2025, 10:02pm UTC](https://discourse.julialang.org/t/subtyping-directly-in-parametrics-types/129949 "2025-06-17T22:02:47Z")

</div>

Can you explain how I should understand?

---

## [Looking for a simple GUI](https://discourse.julialang.org/t/looking-for-a-simple-gui/129959)

<div class="topic-metadata">

**Author:** [@FSUfan](https://discourse.julialang.org/u/FSUfan)\
**Replies:** 4\
**Last updated:** [June 17, 2025, 11:02am UTC](https://discourse.julialang.org/t/looking-for-a-simple-gui/129959 "2025-06-17T11:02:21Z")

</div>

The screenshot below was created using Python and Qt5. I would like to create something similar with Julia. I looked around for a GUI that would suit my needs. There are many available, but most of them do things I don…

---

## [Problem calling \`HypergeometricFunctions.pFq\`](https://discourse.julialang.org/t/problem-calling-hypergeometricfunctions-pfq/129953)

<div class="topic-metadata">

**Author:** [@Cyan](https://discourse.julialang.org/u/Cyan)\
**Replies:** 3\
**Last updated:** [June 17, 2025, 5:16am UTC](https://discourse.julialang.org/t/problem-calling-hypergeometricfunctions-pfq/129953 "2025-06-17T05:16:25Z")

</div>

I am trying to calculate the 2F1 function, where t is Real and z is a 51x51 array, but HypergeometricFunctions.pFq.((1, t / 2), 2 - t / 2, z) returns an error MethodError: no method matching pFq(::Tuple{Int64, Float6…

---

## [Best method for creating many columns in dataframe for dummy variables](https://discourse.julialang.org/t/best-method-for-creating-many-columns-in-dataframe-for-dummy-variables/129940)

<div class="topic-metadata">

**Author:** [@Snowy](https://discourse.julialang.org/u/Snowy)\
**Replies:** 1\
**Last updated:** [June 16, 2025, 10:17pm UTC](https://discourse.julialang.org/t/best-method-for-creating-many-columns-in-dataframe-for-dummy-variables/129940 "2025-06-16T22:17:02Z")

</div>

Hi, I’m working on a problem that requires creating a lot of dummy variables (30+) based on dates and I’m wondering if my approach is optimal. Currently I am creating each variable as a set with the dates that correspo…

---

## [Flux.jl manual training loop results in \`error gradent(F, ::Params) are deprecated\`](https://discourse.julialang.org/t/flux-jl-manual-training-loop-results-in-error-gradent-f-params-are-deprecated/129921)

<div class="topic-metadata">

**Author:** [@Smara\_Kazenango](https://discourse.julialang.org/u/Smara_Kazenango)\
**Replies:** 2\
**Last updated:** [June 16, 2025, 7:16pm UTC](https://discourse.julialang.org/t/flux-jl-manual-training-loop-results-in-error-gradent-f-params-are-deprecated/129921 "2025-06-16T19:16:58Z")

</div>

I have tried the below training loop in Julia and consistently receiving an error gradent(F, ::Params) are deprecated in Flux. How do I solve this error: epochs = 10 for epoch in 1:epochs epoch\_loss = 0.0 for (x\_bat…

---

## [Julia can't find Qt6 DLL](https://discourse.julialang.org/t/julia-cant-find-qt6-dll/129916)

<div class="topic-metadata">

**Author:** [@flewer](https://discourse.julialang.org/u/flewer)\
**Replies:** 8\
**Last updated:** [June 16, 2025, 6:40pm UTC](https://discourse.julialang.org/t/julia-cant-find-qt6-dll/129916 "2025-06-16T18:40:30Z")

</div>

Hello, This problem has been seen multiple times, however this has has not been resolved as far as I am aware. When installing Plots by using Pkg; Pkg.add("Plots") the installation fails because of Qt6 library files …

---

## [Problem with length()](https://discourse.julialang.org/t/problem-with-length/129938)

<div class="topic-metadata">

**Author:** [@FSUfan](https://discourse.julialang.org/u/FSUfan)\
**Replies:** 6\
**Last updated:** [June 16, 2025, 6:31pm UTC](https://discourse.julialang.org/t/problem-with-length/129938 "2025-06-16T18:31:59Z")

</div>

Below is a piece of code that I use to analyze values retrieved from MySQL and placed in a data frame. The if… part is still in its infancy, so please don’t judge it too harshly. val = df\[!,"d8"\] println("val ", v…

---

## [Using Plots in Google Colab gives error](https://discourse.julialang.org/t/using-plots-in-google-colab-gives-error/129933)

<div class="topic-metadata">

**Author:** [@AI\_hayasaka](https://discourse.julialang.org/u/AI_hayasaka)\
**Replies:** 0\
**Last updated:** [June 16, 2025, 2:22pm UTC](https://discourse.julialang.org/t/using-plots-in-google-colab-gives-error/129933 "2025-06-16T14:22:56Z")

</div>

I did using Plots in Google Colab. Got this error: Julia Colab Error - Pastebin.com (I couldn’t paste the whole error here) Is this error because Colab doesn’t have Qt components and that’s why?

---

## [Column read from dataframe is not equal to my string](https://discourse.julialang.org/t/column-read-from-dataframe-is-not-equal-to-my-string/129923)

<div class="topic-metadata">

**Author:** [@FSUfan](https://discourse.julialang.org/u/FSUfan)\
**Replies:** 2\
**Last updated:** [June 16, 2025, 1:10pm UTC](https://discourse.julialang.org/t/column-read-from-dataframe-is-not-equal-to-my-string/129923 "2025-06-16T13:10:16Z")

</div>

I read a MySQL table whose values change frequently and put them in a dataframe (df). In my example, the content of the “d8” column is definitely equal to “GM.” As mentioned above, the value of “d8” can vary, so I need …

---

## [Is there a @parallel macro to parallelize independed expressions in a block?](https://discourse.julialang.org/t/is-there-a-parallel-macro-to-parallelize-independed-expressions-in-a-block/129861)

<div class="topic-metadata">

**Author:** [@mwlidar](https://discourse.julialang.org/u/mwlidar)\
**Replies:** 8\
**Last updated:** [June 16, 2025, 11:20am UTC](https://discourse.julialang.org/t/is-there-a-parallel-macro-to-parallelize-independed-expressions-in-a-block/129861 "2025-06-16T11:20:44Z")

</div>

I’m looking for a macro, call it @parallel here, that transcribes code like this: @parallel begin res1 = expr1 res2 = expr2 … resN = exprN end into tsk1 = Threads.@spawn expr1 tsk2 = Threads.@spawn exp…

---

## [Dispatch on keywords](https://discourse.julialang.org/t/dispatch-on-keywords/129854)

<div class="topic-metadata">

**Author:** [@Cyan](https://discourse.julialang.org/u/Cyan)\
**Replies:** 6\
**Last updated:** [June 14, 2025, 8:34am UTC](https://discourse.julialang.org/t/dispatch-on-keywords/129854 "2025-06-14T08:34:01Z")

</div>

I wrote these two functions function test(;e::Float64) return e^2 end function test(;e::Int) return e\*2 end I obtain the right answer when test(1.) or test(1), but the test(e=1.) returns an error of: TypeErro…

---

## [Problems about using modules in same file](https://discourse.julialang.org/t/problems-about-using-modules-in-same-file/129865)

<div class="topic-metadata">

**Author:** [@Cyan](https://discourse.julialang.org/u/Cyan)\
**Replies:** 4\
**Last updated:** [June 14, 2025, 4:10am UTC](https://discourse.julialang.org/t/problems-about-using-modules-in-same-file/129865 "2025-06-14T04:10:57Z")

</div>

I tried code like this module moduleA function f1() println("test") end end module moduleB function f2() moduleA.f1() end end moduleB.f2() but it turned out ERROR: UndefVarError: \`mod…

---

## [Disable extra information when using @warn](https://discourse.julialang.org/t/disable-extra-information-when-using-warn/129826)

<div class="topic-metadata">

**Author:** [@gitboy16](https://discourse.julialang.org/u/gitboy16)\
**Replies:** 9\
**Last updated:** [June 14, 2025, 2:42am UTC](https://discourse.julialang.org/t/disable-extra-information-when-using-warn/129826 "2025-06-14T02:42:25Z")

</div>

Hi, When I use @warn it prints the warning but also where it happened in the script. Is there a way to disable that information about the line in the script? Thank you.

---

## [Loading 60k images from a folder. Python code is way faster than Julia](https://discourse.julialang.org/t/loading-60k-images-from-a-folder-python-code-is-way-faster-than-julia/129867)

<div class="topic-metadata">

**Author:** [@AI\_hayasaka](https://discourse.julialang.org/u/AI_hayasaka)\
**Replies:** 11\
**Last updated:** [June 14, 2025, 1:31am UTC](https://discourse.julialang.org/t/loading-60k-images-from-a-folder-python-code-is-way-faster-than-julia/129867 "2025-06-14T01:31:25Z")

</div>

This is the code i have currently: using Images function createDataset(path) X = \[\] y = \[\] for label in readdir(path) for file in readdir("$path/$label") img = load("$path/$label/$file") …

---

## [Model improvement](https://discourse.julialang.org/t/model-improvement/129855)

<div class="topic-metadata">

**Author:** [@Smara\_Kazenango](https://discourse.julialang.org/u/Smara_Kazenango)\
**Replies:** 1\
**Last updated:** [June 13, 2025, 3:13pm UTC](https://discourse.julialang.org/t/model-improvement/129855 "2025-06-13T15:13:20Z")

</div>

I am busy analysing the ‘medical\_tc\_test’ and medical\_tc\_train dataset and busy developing a model in Julia. Flux seems to provide very low accuracy and precision rates of below 10%. Has anyone worked on this dataset bef…

[Previous page](https://discourse.julialang.org/c/first-steps/8.md?page=11)

[Next page](https://discourse.julialang.org/c/first-steps/8.md?page=13)